1. Field of the Invention
The present invention generally relates to mesostructured oxide ceramics and the synthesizing method thereof, and particularly to a novel synthesizing method of materials having a mesostructure (mesostructured materials) wherein the wide application in sensors, absorbing agents, catalytic carriers and the like is anticipated, as well as to mesostructured oxide ceramics synthesized with the aforementioned method.
The present invention provides direct synthesizing technology of mesostructured materials at low temperature enabling the formation of a mesostructure of various compound oxides that was difficult with conventional methods.
2. Description of the Related Art
As a conventional synthesizing method of mesostructured materials, reported is a method of employing metal alkoxide (J. S. Beck, Specification of U.S. Pat. No. 5,507,296 (1991)). The mesostructured material directly obtained with this method is the amorphous material of ceramics, and a non-reacting organic silanol group remains. Moreover, the mesostructured material directly obtained with this method is thermally unstable. Thus, as it is difficult to form a desired structure due to its thermal and chemical unstableness, it is not able to yield sufficient functions as a sensor or catalytic carrier. As another synthesizing method of mesostructured materials, reported is a method of employing hydrolysis of metal chloride (P. Yang et al., Nature, 396, 152-155 (1998)). As this method does not utilize a water-based solvent, organic substance capable of becoming the template and the association thereof is limited. Further, as metal alkoxides and metal chlorides are used, atmospheric control during the synthesis is indispensable.
Meanwhile, although a synthesizing method of mesostructured materials by a homogenous precipitation method employing urea as the precipitant has also been reported (M. Yada et al., Angew. Chem. Int. Ed., 38, 3506-3509 (1999)), the ceramics directly obtained with this method are carbonate. In each of the synthesizing methods described above, as it is necessary to conduct thermal processing at 600° C. or higher in order to obtain chemically stable and highly functional oxides [E. Matijevic and W. P. Hsu, J. Colloid Interface Sci., 118, 506-23 (1987)], there is a problem in that the mesostructure will be destroyed as a result thereof. In addition, it is not possible to incorporate a functional organic compound or a functional group having the functions of absorbing specific wavelengths of light or fluorescence in the organic substance capable of becoming the template or the association thereof. Although considered may be a method of incorporating functional organic substance in the mesostructure after removing the organic substance to become the template, the manufacture process becomes complex, and it cannot be denied that this will be inferior in terms of manufacturing costs.
In light of the aforementioned situation and in consideration of the related art described above, the present inventors have conducted intense study aiming to develop a new synthesizing method of mesostructured materials capable of definitely resolving the problems encountered in the aforementioned conventional synthesizing methods and, as a result, have discovered that their desired goal can be reached by directly extracting oxide ceramics at a low temperature of 200° C. or less by utilizing homogenous precipitation reaction from a ceramics precursor under the coexistence of a nanometer-sized template formed of an organic compound or the association thereof, and arrived at the completion of the present invention based on such discovery.